My 2009 20.5 inch iMac has a faulty temperature sensor that switches it off after it'ss been running for about half hour. Restarting the machine does not help. Once it is warm it keeps switching off. I need to let it cool down which takes long. iStat Pro reads normal temperatures in the 30 to 50 C range. The machine is not overheating, it's the sensor that's wrong.

I took the iMac to the Apple store and they said the faulty sensor is in the logic board, needing replacement of the same. Being a 2009 Mac and with the new one coming out now I decided not to repair id. Cost is more than half a new iMac.

It occurred to me that it might be possible to trick the sensor to read a lower temperature and keep the iMac running… a few hours would be good enough...I seldom run CPU intensive programs so the risk of overheating is low – and in any case the machine useless as is so I might as well take the risk.

Can anyone help with this? Thanks.

Maurimar

Raz0rEdge

12-03-2012 08:48 AM

If the defect was with the sensor itself, since it's on the Logic Board, you cant easily replace it and you surely can't fool it. Depending on how the temp sensor has failed, an increased airflow through the system might give you a little bit of extra time..but you'd have to see the teardown of this year iMac to see if it is even possible to direct the airflow in a manner to make a difference..

chscag

12-03-2012 02:15 PM

Quote:

I took the iMac to the Apple store and they said the faulty sensor is in the logic board, needing replacement of the same. Being a 2009 Mac and with the new one coming out now I decided not to repair id. Cost is more than half a new iMac.

I wonder about that? I'm not disputing what the Apple tech told you but the temperature sensors in most MacBook Pro models are replaceable without having to replace the logic board. I would assume the same applies to the iMac series. I would check out the tear down of your particular machine at iFixit: The free repair manual and see for yourself.

Gaining entry into any iMac requires some skill and patience and is certainly not an easy task, so keep that in mind.